AussieRV
Member
Hi all,
It appears I?ve had a major primer failure and desperately need some advise please.
In brief - the Alclad parts where put through a very controlled (isolated and timed) process through a Alumiprep bath for 3 minutes, then directly into a water bath for neutralising (not allowing chemical to dry on surface), then directly into an Alodine bath for 2 minutes (2 - 3 seconds exposure to atmosphere in between dunking), then directly back into water bath for neutralising (again not allowing chemical to dry on surface).
The parts were left hanging to cure for over a week and were handled with gloves to eliminate any contamination of oils from hands. All precautions where taken to keep the parts pristine.
The parts where then sprayed with Shirwin-Williams primer ... CM0483787 primer, CM0120787 adduct, CM0110787 reducer - with precise mixing and induction of 15 minute as per instruction. These primed parts where then left to cure for seven days before handling.
RESULT: During the riveting process, cracking and flaking of the primer appeared around rivets (please see photobucket links below). Interestingly, the primer was coming off with the Alodine treatment attached leaving just the bear aluminium. I then thought that perhaps there was an issue (failure) with the Alumiprep and Alodine treatment ... so proceeded to follow exactly the same process on two separate test samples. After full curing, i bent, deformed and manipulated these test sample to see if i could fail the coating - but not a single fault appeared until the Aluminium reached stress levels. Hence, this leads me to believe the primer may be the cause - as it appears to be brittle.
That said, it seems the primer is bonding to the Alodine extremely well, however the primer seems brittle and is departing with the Alodine coating ... i'm puzzled how the primer is pulling the Alodine off the Alclad?
Can someone can please shed some light on this dilemma.
Cheers,
Matt
http://i1188.photobucket.com/albums/z401/matt-ally/P1070292.jpg
http://i1188.photobucket.com/albums/z401/matt-ally/P1070288.jpg
http://i1188.photobucket.com/albums/z401/matt-ally/P1070291.jpg
It appears I?ve had a major primer failure and desperately need some advise please.
In brief - the Alclad parts where put through a very controlled (isolated and timed) process through a Alumiprep bath for 3 minutes, then directly into a water bath for neutralising (not allowing chemical to dry on surface), then directly into an Alodine bath for 2 minutes (2 - 3 seconds exposure to atmosphere in between dunking), then directly back into water bath for neutralising (again not allowing chemical to dry on surface).
The parts were left hanging to cure for over a week and were handled with gloves to eliminate any contamination of oils from hands. All precautions where taken to keep the parts pristine.
The parts where then sprayed with Shirwin-Williams primer ... CM0483787 primer, CM0120787 adduct, CM0110787 reducer - with precise mixing and induction of 15 minute as per instruction. These primed parts where then left to cure for seven days before handling.
RESULT: During the riveting process, cracking and flaking of the primer appeared around rivets (please see photobucket links below). Interestingly, the primer was coming off with the Alodine treatment attached leaving just the bear aluminium. I then thought that perhaps there was an issue (failure) with the Alumiprep and Alodine treatment ... so proceeded to follow exactly the same process on two separate test samples. After full curing, i bent, deformed and manipulated these test sample to see if i could fail the coating - but not a single fault appeared until the Aluminium reached stress levels. Hence, this leads me to believe the primer may be the cause - as it appears to be brittle.
That said, it seems the primer is bonding to the Alodine extremely well, however the primer seems brittle and is departing with the Alodine coating ... i'm puzzled how the primer is pulling the Alodine off the Alclad?
Can someone can please shed some light on this dilemma.
Cheers,
Matt
http://i1188.photobucket.com/albums/z401/matt-ally/P1070292.jpg
http://i1188.photobucket.com/albums/z401/matt-ally/P1070288.jpg
http://i1188.photobucket.com/albums/z401/matt-ally/P1070291.jpg